In this case, the President was officially informed at 9:20 ET last night that they had confirmed Z's death. As early as 5 or 6 yesterday afternoon he had been told that they had good reason to believe the monster was dead, but were awaiting absolute confirmation.
So the President did not have to be awakened in the middle of the night. He knew way before the rest of us.
Generally speaking, if something does come up in the middle of the night, the National Security Advisor takes the call if it is a security matter. Don't know who takes it if a domestic crisis...probably the Chief of Staff. Then they decide whether the situation is so pressing that the President has to be awakened from sleep.
Thanks...I have always been a "how does it work" person. My brain is full of irrelevant details--not much room left for the important stuff, LOL!